Numerous studies have shown that glucocorticoids inhibit reproductive function; however, only limited attention has been given to the possible sites and/or mechanism of this action. The overall objective of the proposed work is to obtain basic information regarding the nature of the interrelationships which exist between glucocorticoids and reproductive function. In vivo studies will be designed to compare the efficacy of various glucocorticoids (natural and synthetic) to inhibit gonadotropin secretion, and to investigate possible interactions between glucocorticoids, gonadal steroids and luteneizing hormone releasing hormone (LHRH) on LH release from the anterior pituitary. In addition, two in vitro techniques for studying pituitary function will be established, namely, enzymatically dissociated pituitary cell suspension, and a pituitary perifusion system. These in vitro techniques will be used to investigate the roles of Ca ions and cyclic AMP in mediating the release of gonadotropins in response to LHRH, and how these roles are influenced by steroid hormones.